hey guy's i to a problem with my 360 in my 77 power wagon, I made a first long haul today lol 50 mile's total an she was running hot 250 deg, made it to where I needed to go so let it sit for a bit filed it up with water an I bypassed the heater core thinking maybe that's plugged, on the way home same thing I had to stop again let it sit fill it back up, when It's driven in town 20-25mph no problem's.. hell it's only 66-70 deg out.. also I removed the t-stat. thinking maybe water pump but it also has a flex fan on it, what's your guy's take on those?? I hate them but if they are a upgrade from the clutch fan then I will leave it but if not then I will throw a clutch fan in her

Hot moving and cool in town usually means plugged or too small radiator. The fan doesn't help much when moving... your OE fan setup is likely much better than a flex fan.

How's old is the radiator and how does it look? That's what I would check first.

do you have any surge at cruising speeds? A lean engine will generate a lot of heat. This kind of thing can show up on a shake down run.

no shaking nothing, I thought maybe timing but she fire's up good first turn of the key.. the radiator is stock/factory I just aint a fan of them flex fan's because they flatten out at at rpm range, the flex fan was on it when I bought it but I got a clutch fan off my 90 318 I could put on it..

Sure the flex fan is a problem, get it off of there. But I bet that's not the main problem. Like what was mentioned, I bet it's lean under power. It won't last long like that. Easy fix, richen up the carb and see if we are right. It pretty easy and cheap to try.

What Ahy said & it'd have to be pretty badly plugged. On the lean issue take out the metering rod springs & block the pistons up & try it out. Holler how it goes

Put the thermostat back in.

will mess with the carb tomorrow, pulled the flex fan off, also pulled the lower radiator hose off an stuck my garden hose in the top an seamed to flow good lol, I pulled the t-stat thinking maybe it was sticking... will update as soon as I get her buttoned up.

there is no leak's I had to fill it up because it kept's boiling out lol, I got a buddy that has a extra radiator out of a power wagon so im going to throw it in while I have the fan out, might as well..

My money is on bad radiator. I bet that takes care of it.

Sometimes you may never find the problem even after replacing "everything." In my GTX I rebuilt the carb and all jetting, air intake, water pump, recored 3 row 26" factory stock radiator, fan/clutch, TStat, shroud, hoses, belts, pulley, fuel pump, all high voltage delivery items, using coolant of 90% demin water with Redline water wetter, optimized timing adjustments, and even putting the cam shaft back to 100% factory stock to reduce engine power. Never solved the problem of overheating at idle on hot summer days. Lived with it for 3 yrs before selling the car. Used an overflow container to prevent leaving puddles at shows. The only step I didn't take was an oversized aluminum radiator with a much higher heat dissipation.

If you run with the heater core at full bore and it keeps your operating temp a bit lower than when it is off, you probably have decent flow through it. If your radiator is gunked up you should be able to see signs of blocked channels at the top of the core.

Plugged heater core wouldn't be an issue here.

Running hot at speed it usually water flow related. Wrong pulleys, wrong pump, radiator flow issue, thermostat not opening up are probable issues.

Since you removed the thermostat it's probably not the issue, but put one in. What, if anything changed since it last ran right?

One other thing, I had a non-opening exhaust flapper that drove me nuts trying to find my "overheating" problems. If you have one make sure it is free to move AND the spring that opens it works (my spring had the tail broke off).